Process of treating rubber and product obtained thereby



Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE SIDNEY M. CADRVELL,or LEONIA, NEW annsnxnssremon TO. THE NAUGATUox v CHEMICAL COMPANY, ornucnrucx, CONNECTICUT, *A CoRronArIoN' or CON- EC'rICUr rnocnss orTREATING RUBBER. AND rnontrcr' OBTAINED THEREBY No Drawing. Originalapplication filed March 2, 1928, Serial No. 258,670. Divided and thisapplication filed March 2, 1928.

This case is a division of case Serial No. 258,670, filed March 2, 1928;

This invention relates to the treatment of rubberand similar materialsand to the proclucts obtained thereby. 7

An object of the invention is to accelerate the action of the newchemical compounds by the introduction of a base. A further object is toprovide a method whereby the basic material may be introduced intorubber.

In the present practice of the use of accelerators, it is generallyknown that many of the compounds employed are so powerful ployed in hotvulcanization, for exampleat 212 or thereabouts. Illustrations of suchrapid accelerators are metallic dithiocarbamates, metallic salts ofother thioacids, mercapto thiazoles and the like. According to thepresent invention this serious objection of prevulcanization may beentirely overcome, the rubber compounds may be mixed upon the mill withpractically no danger of-prevuL canization thereon, without sacrificingthe accelerating power which is desired. Certain of the compoundsforming the. subject matter of the present invention may be mixed withrubber with entire safety on the mixing mills, subject to the conditionshereinafter named, whereas others may be safely mixed, observing certainprecautions as to mill temperature, etc. I V

The invention includes combining rubber and similar vulcanizablematerials with a vulcanizing combination, including a vulcanizing agent,a metallic oxide or its equivalent, and a substance containingtheradical RCSY r V Y and vulcanizing the rubber. The invention alsoincludes the products This serious disad- Serial No. 258,681.

any bivalent element suchas sulphur or oxygen, or a trivalent elementasin the case of a thiazole; R. and X mayor mayv not be parts of aring.Y is a carbon atom attacheduat theSofthe I RCS radical, and is notdoubly bonded to sulphur or oxygen but is a carbon atom of a cyclic ormethyl group s o substituted that the whole compound whichcomprises theradical nCsY V will react at the thiol sulphur-carbon bond, e., at SY,with sodium hydroxide in' boiling aqueous alcohol at least as rapidly asdiacts under the same conditions I I The invention further consists inaccelerating the action of thecompounds by the additionof basicmaterials. The invention further consists in introducing basic materialsv thus I eptg n d 7 phenylmethyl dimethyl dithiocarbamate reor thecompounds herein disclosed by difiusion from rubber or fromanysurrounding medium. p r;

g It Will be seen from the list of compounds is nitrogen in thexanthogenates'R is oxye in the dithiobenzoates R is Carbon, and

in the mercapto thiazoles R is sulphur; X is sulphur in thedithiocarbamates,xanthogenates, and dithiobenzoates, and is the substigiven below that in the dithiocarbam ates B compounds may beconveniently illustrated as follows:

are among the metallic compounds which may be used.

RCSY

Y: a carl bon atom in a substituted cyclic group ."Asfillustrations ofgroups comprising Y inwhich Yis'a carbon atom in a substituted cyclicgroup, the following may be given: 2-4 dinitrophenyl, 2-6 dinitro .4chlorophenyl, 2-4-6 trinitrophenyl '(picryl) etc. As illusitrations inwhich Y is the methylcarbon atom in a substituted methyl group, thefollowing may be given z-diphenyl methyl, triphenyl methyl, phenylmethylene (benzal) trimethyl methyl (tertiary butyl) phenyl chlormethylene, phthalimido methyl, diiodomethyl, allyl, etc.

In the polynitro phenyl substitutions, it willbe observed that the threesubstitutions :given above have .one ,nitro group ortho to the1.-position, and at least one of the remain- :ing substituents meta tothe aforesaid nitro group; Inthedinitro phenyl compounds, the itwfo.n'itro groups are meta to eachother, and one of them is ortho to the1-position. All of these compounds-may be prepared according to the samegeneral procedure, namely, treating a solution of a salt (preferably thesodium salt) ofthe thiol acid, thiazole, xan- "tho'gen'ate,dithiobenzoate, etc.,with a solution'-"of=the chloride of thesubstituted group comprising For example, a solution of sodium dimethyldithiocarbamate may be treated with a solution of 2-4 dinitro chlorbenzol or a benzal chloride.

. .Thewhole compound such as 2,4 dinitrophenyl dimethyl dithiocarbamatereacts at least as rapidly with sodium hydroxide in boiling :a'queousalcohol as diphenylmethyl dimethyl dithiocarbamate reacts under the sameconditions. All the compounds which react :with sodium hydroxideat leastas rapidly ;a-s I diphenylmethyl dimethyl dithlocarbamate,;acceleratevulcanization, in-the presence of 'a-metallic oxide, such aszlnc ox deor ,anreq'uivalent metallic compound.

Zinc oxide is a good illustration of a methe. mercuric :state, leadpreferably in the plumbous. state,cadmium, copper preferably inthecupricstate, arsenic preferably in the .xarsenous state,,-manganesepreferably 1n the manganous state. Preferably the metallic;.compound is of such a nature that the metallic element is availableduring the vulcanization process. Oxides, stearates, carbonatestriethanolamine.

I Y: a carbon atom in a substituted methyl group The compounds disclosedherein function 'well when the cure is carried out according to any ofthe commercial methods suchas in steam, talc, water, etc.

I have observed that the action of the compounds disclosed .herein isaccelerated by the presence of a small amount of a basic material suchas sodium hydroxide, trisodium phosphate, dicyandiamide, piperidine,

increases the tensile strength at all temperatures of vulcanization byabout. 10%. For instance a stock made up of 100 parts of pale crepe, 10parts of zinc oxide, 3 partsof sulphur and .25 part of 2,4 dinitrophenyldimethyl dithiocarbamate gave, in one in stance a tensile of 1235 poundsper square inch after 60 minutes at 5 pounds steampressure and'2980pounds after 60 minutes at 40 pounds steam pressure. In one instance .07part=ofsodium hydroxide wasadded and the tensile after minutes at5poundssteam pressure was 3465 pounds and after60 minutesat 40 poundssteam pressure the tensile was 3365 pounds. When one part of'sodiumhydroxide was added to the stock it cured at ordinary temperatures inless than a Week and gave a tensile of 4935 pounds after -60 minutes at5 pounds steam pressure. .15 part of .piperidine was added instead ofthe sodium hydroxide and the stock gave a tensile of 4740 pounds after60 minutes at 10 pounds steam pressure, 55.50 pounds after 60 minutes at20 pounds. steam pressure and 4300 pounds after 60 minutes at 40 poundssteam pressure.

The effect of the base on these dinitrophenyl compounds is much moremarked than it is upon other accelerators such as tetramethylthiurammonosulphide, diphenylguanidine, acetaldehyde aniline condensationproduct or heptaldehyde aniline condensation product.

Since a basic material accelerates the actionof ithe'accelerator andlowers the tem-,

perature at which it functions, it also increases the speed of burningon the mixing mill. Therefore the greater the amount of base present inthe mix, the greater the danger of burning on the mixing mill andrubbers which are basic therefore accelerate the action of thesecompounds. Burning on canization operation. :-This is particularly trueof the polynitrophenyli compounds.

Instead of adding on the mixing roll-the basic materials intended toactivate the compounds or accelerate their action, onemay permit thebasic material to diffuse into the rubber. For instance if the stock?given above for vulcanization in. the air be vulcanized in aircontaining ammonia, the vulcanization is greatly acceleratedandthesurface of the stockis remarkably hard and'resistant to marring.The introduction of the basic material may be made on the millby'diifusionfrom a liquid solution, or gas, or from a'd oinlng rubberstock or from a fabric. e a

As another-ex-ampleyl make the compounds in the usualmanner consis'tingof 100 parts of pale crepe, 1O parts-of zinc oxide,-3 p'arts of sulphurand 2 parts of 2,4 'dinitrophenyl dimethyl dithiocarbamate.

stock'in the form of a sheet .060 thick or in the form of an article maybe treat-edwitb gaseous ammonia for lfi'hours. Thereafter it willvulcanize at 212 Fwmuch more'rapidly than a stock not 50 treated.Instead of gaseous'ammonia, I may employ aqueous ammonia, aqueousdiethylamine, aqueous anlllne or dlmethylamlne or aniline vapor.

It is believed that these basic materials diffuse into the rubber andaccelerate the action of the dinitrophenyl dimethyl dithiocarba- Y mate.

7 Similar results have been obtained with 2,4 dinitrophenyl benzothiazylsulphide. The action of the bases is most marked withthe'polynitrophenyl compounds-but the bases alsofunction with the othercompounds disclosed herein such as 'triphenylmethyldictl'iyl-dithiocarbamate forinstan'ce.

As an example of the introductionby diffusion of the basic materialaswell asfthe lintroduction by difl'usion'of some ofthe comp'oun'dsdisclosed herein, the following illus- ;tration is given; 100 parts ofpale crepe,l

parts of zinc oxide, 3 parts of sulphur, 1 part of 2,4 dinitrophenyldimethyldithiocarbamate and- .2 part of monochlor acetic acid arenmxedto form one stock which is calendercd toa thickness of.0lO Another stockis-made up of 100 partsof pale crepe, 10 T 'p-a'rts'of zinc oxide, 3parts of sulphur, and

This

4 parts" of dibenzyl'amine. This stock is mixed on the mills in theusual mannerand calendered to athickness of .010. The two stocks areplied up alternately using 3 plies of each and allowed to stand for 24hours to permit the diffusion of the dibenzylamine into thedinitrophenyl stock-and of the dinitrophenyl dimethyl. .dithiocarbarnateinto the dibenzylamine stock. Thereafter the plied,- up stock is heatedat 212 and it is found that vulcanization occurs much more quickly thanit does for. the individual stocks which have not been plied up. It willbe observed that the dibenzylamine acts to neutralize the monochloracetic acid as well as activate the dinitrophenyl dimethyldithiocarbamate.

As pointed out before the presence of the monochlor acetic acid improvesthe resistancefi' to burning but the procedure may also be carried outwithout the use of the acid- Other compounds disclosed herein may besubstituted for the compounds given above. The basic material (ammonia,etc.) may be introduced from the surrounding medium sucli asairor waterto neutralize the acids,

and/or to activate the accelerator. For instance if .2 part-of acidbeadded to the stock for air cure given above, and-the stock be cured inair containing ammonia gas, the ammonia will not only neutralize theacid but will activate the dinitrophenyl compound. The basic materialmay be introduced in any desired manner at any time prior to completevulcanization, i. e., it may be introduced during: vulcanization as agas or vapor, or it may beapplied to the stock by painting, dipping, .orblending in cement form, etc. before the stock is subjectedtovulcanization, or the stock may be vulcanized in a solution orsuspension of the basic material.

It is echoved that the dinitrophenyl compounds are particularlysusceptible to the action of acids and alkali-es because thedinitrophenyl compounds of all sorts of acids according to the processesdisclosed are: 2,4 dinitrophenyl diethyl dithiocarbamate (M. P. 81 6:) I

2,4 dinitrophenyl dinormal propyl dithiocarbama-te P. 84 C.) r

2,4 dinitrophenyl di-isobutyl dithiocarbamate (M. 'P. 85 C.)

7 2,4 dinitrophenyl dinormal butyl dithiocarbamate.

2,4 {dinitrophenyl di-iso f amyl dithiocarbamate P. 5254 C.) v I v I,2,4 dinitrophenyl dibenzyl dithiocarbamate (M.P. 106?- C.)

'2,4 dinitrophenyl morpholine dithiocarbamate PL'125130 C.)

Other compounds which may be employed 2,4 dinitrophenyl idicyclohexyldithiocarb'amate (M. P. '127"C;) 1

2,6 idinitro tchloro phenyl diethyl dithiocarbamate (M. P. "123 0.)

It will be noted that in these compounds,

thenitrogeniatom holds atleast one aliphatic -or alkyl group and ispreferably disubstititted. These compounds :may also be 're- .garded as'thiol esters, the ester group being attached to the thiol sulphur; Theyare il- :lustrativepf compounds containing .RCSY,

*Whe'reRis nitrogen and X is sulphur.

Further K examples include organic derivatives of aryl thiazolesz 2,4dinitrophenyl 'benzothiazyl sulphide 2,6 -dinitro 4 chlorophenylbenzothiazyl sulphide '(M. -P. 167 0.)

Allyl benzothiazyl sulphide (B. P. 145- 'Dip'heny lmethylbenzothia-zylsulphide (M.

The last mentioned compounds illustrate 30 compounds in which R and X ofthe group RCSY it are joined, and R=S; X='N. In this instance thegeneral group may be Written I ROSY wvhere Rand X-are parts of a ring.They contain the group Other derivatives may also-{be used.

henylmethyl di- P. 0.), triphenylmethyl di-isoamyl di- .thiocarbamate P.89-90 "triphenylj methyl dinormal :propyl dithiocarbamate zothiazyl-.dithiocarbamate and mean? i PP. 66- 67 G4), diphenylmethyldimethylzdithiocarbamate :(M. "P. 96.54)? GJ) :Ano'ther type is shown intertiary butyl diethylidithiocarbamate. I 4

Still further :groups are illustrated zby :allyl diethyl.dithiocarbama'te. (B. :P. 1 10-'1l l 1C).), phthalimido 'methyldiethyl-dithiocarbamate (M. :P. 122 0.), di-iodo methyl-dimethyl.dithiocarbamate (M. P. 76

C.) ,and trimeth-yl methyldiethyl dithiocarbamate respectively.

Triphenylmethyl ethyl :xanthogenates and 2,6 dinitro 1.4: chlorophenyldithiobenzoate also accelerate vulcanization and constitute examples .of:Xanthogenates, (11 6, X=S), :and'dithiobe'nzoates1(R= C, X='S) All oftheabovelcompounds are new cheniicals, not recordedin the literature.The

preparation of these-materials forms the subjQCtl'DfllltGI of separateapplications.

All 'of-theabove mentioned compoundsare accelerators of vulcanization.Some of-them give hig'htensilestrength and other Valuable physicalproperties such as improved "resistance to abrasion, ageing, and otherproper ties. The Iclaimsare therefore to be broadly interpreted asincluding such treatment:of rubber in .any -form (solid, solution,dispersion) for these purposes, as Well as for'vulcanization, :in which.latter instance, it is1un-' dersto od that a *vulcanizing agent :and 1a:metallic-oXideoritsequivalent Will be added .to-the rubber, and anantioxidant or other material improving the physical lproperties 'of therubber may be present, if desired. It isof course understood'that'notall'of' these compounds are of equal accelerating strength,

pound for pound,under identical vulcanizing conditions. Theseaccelerators may be used in eonj unction with any of the :knownantioxidants and other' materials introduced'into rubb'erto improveageing and-other physical properties.

Diphenyl :methyl dimethyl dithiocarbamate, diphenyl -methyl diethyldithiocarbamate, diphenyl methyl benzothiazyl sulphide, all-yl diethyldithiocarbamate, allyl 'bensulphide accelerate, but :the degree ofacceleration is very small,

and atjpresent'is regarded as of no commer- T cial importance.Phthalimido methyl diethyl dithiocarbamate accelerates vulcanizationsomewhat more than the diphenyl *methyl compounds, and ithydrolyzessomewhat more rapidly than diphenyl methyl dimethyl dithiocarbamate.Methyl dimethyl ethyl benzothiazyl sulphide are examples of compoundswhich -do not hydrolyze as rapidly as diphenyl methyl dimethyldithioearbamate in the herein described test, and the pure com- ;poundsdidnot accelerate vulcanization un- The accelerating compounds ingeneral may be used in amounts varying between der the conditions givenabove asexamples. I

fi; and 2 parts on 100 parts of rubber, depending of course on the typeof stock, etc. It is believed that, in general, as the molec-' ularweight of the groups attached to the nitrogen is increased the higher isthe vulcanizing temperature, when equi-molecular amounts of acceleratorare considered, and the more resistant are the compounds toprevulcanization on the mixing mills, andthe better is their action withlitharge in the absence or presence of zinc oxide. The rate of reactionof the compound with sodium hydroxide in boiling aqueous alcohol may bedetermined as follows: a

.00125 moles of the compound is weighed into a cc. Erlenmeyer; 25 cc.alcohol and .00125 moles sodium hydroxide in the form of anapproximately normal solution are added and the solution brought tojtheboiling point as quickly as possible and kept there for exactly-30minutes. The solution is then cooled quickly and titrated withapproximately acid, using phenolphthalein as the indicator. Carbondioxide-free water should be used throughout. A blank should be run inorder to check up on the amount of acid necessary to neutralize thesodium hydroxide when no compound is used. The decrease in hydroxyl ioncontent during the boiling is taken as a measure of the extent of thereaction with sodium hydroxide.

The above procedure constitutes a method whereby the relative rate ofhydrolysis of any given compound of the types disclosed may be comparedwith that of diphenylmethyl dimethyl dithiocarbamate which in turn maybe prepared in accordance with the general procedure indicated herein,that is, reacting together sodium dimethyl dithiocarbamate and diphenylchloro methane.

Having thus described my invention what I claim and desire to protect byLetters Patent is:

' 1. A method of treating rubber which comprises adding to rubber avulcanizing combination including a compound containingthe group i RCSY,

in which R represents either N, O, or C or further represents when X isN; X represents O or S, or further represents N when R is S; and Yrepresents a carbon atom in a substituted cyclic group, or in asubstituted methyl group that does not contain 0 or S doubly bonded toY, which compound hydrolyzes in aqueous alcohol in the presence ofsodium hydroxide, at least as rapidly as di-' phenyl methyldimethyldithiocarbamate under the same conditions, and carrying out thevulcanization of the rubber in the presence of a basic materialintroduced thereinto.

2. A method of treating rubber which comprises addin' to rubber avulcanizingcombination includ group RCSY;

in which It represents either N,O, or Cor further representsS when X' isN; X repre sents O or S, or further represents N when bination includinga compound containing; the group Rosy. V

in which R is N; X is S and Y represents a carbon atom in a substitutedcyclic group, or,

in a substituted methyl group that does not contain 0: or S doublybondedto Y, whichv compound hydro-lyzes in aqueous alcohol in the presence ofsodium hydroxide, at least as rapidly as diphenyl methyl dimethyldithiocarbamate under the same conditions, and carrying out thevulcanization of the rubber in the presence of a basic materialintroduced thereinto.

4:. A method of treating rubber which comprises adding to rubber avulcanizing combination including a compound containing-the grouprapidly as diphenyl methyl dimethyl dithio-- carbamate under the sameconditions, and further introducing a basic material into the rubberstock prior to complete vulcanization.

5. A method. of treating rubber which comprises adding to rubber avuldanizingcombi nation including a compound containing the group ResY,

in which Rrepresents either N,j(), or C or further represents S when Xis, repreing a compound containing the sents 0 MS, or'further representsN when R is S ;.and Y representsa carbon atom in a substituted arylgroup, or in a subst tuted methyl group that does not contain O or Sdoubly bonded to Y, which compoundhydrolyzes in aqueous alcohol in thepresence of sodium hydroxide, at least as rapidly as diphenyl methyldimethyl dithiocarbamate under the same conditions, and carrying out thevulcanization of the rubber in the presence of a bas c materialintroduced thereinto.

6. A method of treating rubber which comprises; adding torubbera'vulcanizing combination including a' compound containing the group vin which R represents either N, O, or C, or further represents S when Xis N; X repre sents O or S, or further represents N when R is S; and Yrepresents a carbon atom in a substituted phenyl group, or in asubstituted methyl group that does not contain 0 or S doubly bondedto Y,which compound hydrolyzes in aqueous alcohol in the presence of sodiumhydroxide,-;atleast as rapidly as diphenyl methyl dimethyldithiocarbamate under the same .conditions,.and carrying out thevulcanization of the rubber, in the presence ofa basic materialintroduced th-ereinto.

7 A method of treating rubber which comprisesadding to rubber avulcani'zing combination includinga compound containing the group RCSY,

, v v inwhich R represents either'N, O, or C or further represents Swhen X is N; X represents O or S, or further represents N when R is S;andY represents a carbon atom in a poly nitrophenyl group, or in asubstituted methyl group that does not contain O'or S doubly bonded toY, which compound hydrolyzes in aqueous alcohol in the presence ofsodium hydroxide, at least. as rapidly as diphenyl methyl dimethyldithiocarbamate under the same conditions, and carrying out thevulcanization of the rubber in the presence of a basic materialintroduced thereinto.

8. A method of treatingsrubber which comprises adding to rubber avulcanizingcombination including a compound containing thegrou ROSY,

it 7 r in which R is N; X is S and Y'represents a carbon atom in a polynitrophenyl group, or in a substituted methyl group that doesnot contain0 or S doubly bonded to Y, which compound hydrolyzes in aqueous alcoholin the presence of sodium hydroxide, at least as rapidly as diphenylmethyl dimethyl di thiocarbamate' under the same conditions,

and carryingl'outithe" vulcanization. Of? the rubber'in the presence-ofa basic material in.- troducedathereinto.

I 9'. A method of treating rubber which'comprises addingto rubber avulcanizingcombination includinga compound containing;

the group 7 i iu sY,

in which R represents either N, O, or C or further represents S when Xis N; X represents O or S, or further represents N when R is S; and Yrepresentsa carbon atom in a substituted cyclic group, or in asubstituted methyl group that does not contain 0 or S. doubly bonded toY, which compound hydrolyzes in aqueous alcohol in the presenceof-sodium hydroxide, at least as rapidly as diphenyl methyl dimethyldithiocarbamate under the same conditions, and vulcanizing in thepresence of ammonia.

10. A method of treating rubber which comprises adding to rubber avulcanizing combination including a compound containing the group IRosy,w

in which R representseither N, O; or C or further represents S when XisN; X represents O or S, or further represents N when R is S; and Yrepresents a carbon atom in a substituted aryl group, or in asubstituted methyl group that does not contain O or S doubly bonded toY, which compound hydrolyzes in aqueous alcohol in the presence ofsodium hydroxide, at least as rapidly as diphenyl methyl dimethyldithiocarbamate under the same conditions, and vulcanizing; in thepresence of ammonia.

12. A method of treating rubber which comprises adding to rubber avulcanizingcombinationincluding a compound containing the group RcsY,

in which R represents either N, O'or G or further represents S when X isN; X represents O or S, or further represents N" when in the presence ofammonia.

13. A method of treating rubber which comprises adding to rubber aVulcanizing combination including a compound containing the group iRCSY,

in which R represents either N, O or C or further represents S when X isN; X represents O or S, or further represents N when R is S; and Yrepresents a carbon atom in apoly nitro phenyl group, or in asubstituted methyl group that does not contain 0 or S doubly bonded toY, which compoundhydrolyzes in aqueous alcohol in the presence of sodiumhydroxide, at least as rapidly as diphenyl methyl dimethyldithiocarbamate underthe same conditions, and vulcanizing in thepresence of ammonia. f

'14. A method of treating rubber which comprises adding to rubber avulcanizing combination including a compound containing the group V'RosY,

in which R is N; X is S; and Y represents a carbon atom in a poly nitrophenyl group, or in a substituted methyl group that does not contain 0or S doubly bonded to Y, which compound'hydrolyzes in aqueous alcohol inthe presence of sodium hydroxide, at least as rapidly as diphenyl methyldimethyl dithiocarbamate under the same conditions, and vulcanizinginthe presence of ammonia.

15. The process of producing vulcanized rubber which comprises heatingrubber, a metallic oxide, and a vulcanizing agent in the presence ofa'mixture comprising a basic material and a compound containing thewhere R is sulphur, X is nitrogen, andY is.

a carbon atom in a substituted cyclic group,

or in a substituted methyl group that doesnot contain 0 or Sdoublybonded to Y, which compound hydrolyzes in aqueous alcohol in thepresence of sodium hydroxide, at

organicamine and a compound containing the group where Y is a carbonatom in a substituted cyclic group, or in a substituted methyl groupthat does not contain 0 or S doubly bonded to Y, which compoundhydrolyzes in aqueous alcohol in the presence of sodium hydroxide, atleast as rapidly as diphenylmethyl dimethyl dithiocarbamate under thesame conditions. i v V 17. Thekprocess of producing vulcanized rubberwhich comprises heating rubber, a metallicoxide, and avulcanizing-agentin the presence of a mixture comprising an organic amine and a compoundcontaining the group v 18. The process of producingvulcanized rubberwhich comprises heating rubber, a

metallic oxide, and a vulcanizing agent in the presence of a mixturecomprising a sec ondary amlne acceleratmg compound and a compoundcontaining the group R p-say whereR is sulphur, X is nitrogen, and Y isa carbon atom in a substituted cyclic group, or in a substituted methylgroup that does not contain 0 or S doubly bonded to Y, which compoundhydrolyzes in. aqueous alcohol in the presence of sodium hydroxide,atleast as V rapidlyras diphenyl-methyl dimethyl dithiocarbamate underthe same conditions.

19. The process of producing vulcanized rubber which comprises heatingrubber, a metallic oxide, and a vulcanizing agent in the presence of amixture comprising a secondary amine accelerating compound and acompound containing the group where is the methyl carbonatom of a substituted methyl group that does not contain- 0 or S doubly bonded to Y,which compound hydrolyzes in aqueous alcohol in the presence 01' sodiumhydroxide, at least as rapidly asdiphenyl-methyl dimethyldithiocarbamate where-His sulphur, X is nitrogen, and Y is a carbon atomin a substituted cyclic group, or in a substituted methyl group thatdoes not contain 0" or S doubly bonded to Y, which compound'hydrolyzesin aqueous alcohol in the presence of sodium hydroxide, at

least-as rapidly as diphenyl-methyl dimethyl dithiocarbamate under thesame conditions. 21. The process of producing vulcanized rubber whichcomprises heating rubber, a metallic oxide, and a vulcanizing agent inthe presence of a mixture comprising an aryl substituted secondary amineaccelerating compoundv and a compound, containing the group where Y isthe methyl carbon atom of'a substituted methyl group that does notcontain 0 or S doubly bonded to Y, which compound hydrolyzes in aqueousalcohol in the presence of sodium hydroxide, at least as rapidly asdiphenyl-methyl dimethyl dithiocarbamate under the same conditions.

22. The process of producing Vulcanized rubber which comprises heatingrubber, a metallic oxide, and a Vulcanizing agent in the presence of amixture comprising an aryl substituted secondary amine acceleratingcompound and phenyl methylene bis benzothiazyl sulphide.

9.3. A vulcanization accelerator mixture comprising a secondary amineaccelerating compound and a compound containing the group where Y is acarbon atom in a substituted cyclic group, or in a. substituted methylgroup that does not contain 0 or S doubly bonded to Y, which compoundhydrolyzes in aqueous alcohol in the presence of sodium hydroxide, atleast as rapidly as diphenylmethyl dimethyl dithiocarbamate under thesame conditions.

24-. A. vulcanization accelerator mixture comprising an aryl substitutedsecondary amine accelerating compound and a compound contaming the groupay M where Y is the methyl carbon atom of a sub stituted methyl groupthatd'oes not contain; 0 or-S doubly bonded to Y, which compoundhydrolyzes in aqueous alcohol in the presence of sodium hydroxide, atleast as rapidly as diphenyl-methyl dimethyl dithiocarbamate under thesame conditions.

25. A method of treating rubber which comprises adding to rubber avulcanizing combination including" a polynit-rophenyli compound of adisubstituted dithiocarbamate, which compound hydrolyzes in aqueousalcohol; in thefpresence of sodiumhydroxide' at least as rapidly asdiphenyl methyl dimethyl:

dithiocarbamate under. the same conditions,

and carrying out vulcanization of the rubber: in the presence of a basicmaterlal introduced and carrying out vulcanization of'the rubber- 1n thepresence of a basic materlal introduced" thereinto.

28; A method of treating rubber which comprises adding to rubber avulcani'zi'ng combination including a polynitrophenylcompound of adialkyl dithiocarbamate, which compound hydrolyzes in aqueous alcohol inthe presence of sodium hydroxideat least as rapidly as diphenyl methyldimethyl dithiocarbamate under the same conditions, and carrying outvulcanization of the rubber in the presence of a basic materialdiffusedthereinto.

29. A method of treating rubber which comprises adding to rubber avulcanizing combination including a dinitrophenyl compound of adisubstituted dithiocarbamate, which compound hydrolyzes in aqueousalcohol in the presence of sodium hydroxide atv least as rapidly asdiphenyl methyl dimethyl dithiocarbamate under the same conditions, andcarrying out vulcanization of the rubber in the presence of a basicmaterial introduced thereinto.

30. A method oi treating rubber which comprises adding to rubber avulcanizing combination including a dinitrophenyl dialkyldithiocarbamate; which compound hydrolyzes in aqueous alcohol in thepresence of sodium hydroxide a't' least as rapidly as diphenyl methyldimethyl dithiocarbamate under the same conditions, and carrying outvulcanization of the rubber in the presence of a basic materialintroduced thereinto.

31. A method of treating rubber which comprises adding to rubber avulcanizing agent, a metallic oxide, and a dinitro phenyl compound of adisubstituted dithiocarbamate in which the nitro groups are meta to eachother and one of them is ortho to the CS bond, which compound hydrolyzesin aqueous alcohol in the presence of sodium hydroxide at least asrapidly as diphenyl methyl dimethyl dithiocarbamate under the sameconditions, and vulcanizing the rubber in the presence of a baseintroduced into the rubber prior to complete vulcanization.

32. A method of treating rubber which comprises adding to rubber avulcanizing agent, a metallic oxide, and a dinitro phenyl dialkyldithiocarbamate in which the nitro groups are meta to each other and oneof them is ortho to the CS bond, which compound hydrolyzes in aqueousalcohol in the presence of sodium hydroxide at least as rapidly asdiphenyl methyl dimethyl dithiocarbamate under the same conditions, andvulcanizing the rubber in the presence of a base introduced into therubber prior to complete vulcanization.

33. A method of treating rubber which comprises adding to rubber avulcanizing agent, a metallic oxide, and a 2- dinitro phenyl composed ofa disubstituted dithiocarbamate, which compound hydrolyzes in aqueousalcohol in the presence of sodium hydroxide at least as rapidly asdiphenyl methyl di methyl dithiocarbamate under the same conditions, andfurther introducing a basic material into the rubber during thevulcanization of said rubber.

34. A method of treating rubber which comprises adding to rubber avulcanizing agent, a metallic oxide, and a 2-4 dinitro phenyl compoundof a dialkyl dithiocar- .bamate, and further introducing a basic ma- 50terial into the rubber during the vulcanization of said ruber. V

35. A method of treating rubber Which comprises adding to rubber avulcanizing agent, a metallic oxide, and a 2-4 dinitro phenyl compoundof'a dialkyl dithiocarbamate, and vulcanizing in the presence ofammonia.

36. A method of treating rubber which comprises adding to rubber avulcanizing agent, a metallic oxide, and 2-4 dinitrophenyl dimethyldithiocarbamate, and further 1ntroducing a basic material into therubber during the vulcanization of said rubber.

37. A method of treating rubber which the presence of ammonia.

38. The process of producing vulcanized rubber which comprises heatingrubberarid sulfur in thepre'seh ce of a-mixt'ure cf aceelerators; saidaccelerators comprising thereaction product ofdinitrochlo-rbenze-iie;and alkaline salt of merc'apto-benzo-thiazole,and a basic organic nitrogen-containing vulcanizat-ion accelerator. 39.The process of producing vulcanized rubber which comprises'heatingrubber and sulfur in the presence of a mixture of a cc e'lerators,s'a'id accelerators comprising the reaction product ofdinitrochlorbenzene and the potassium salt of mercapto-ben'zdthiazole,and a basic organic nitrogen-containing vulcanization accelerator. v 40.The processof producing vulcanized rubber which comprises heatingrdb'bfrfind sulfur iii the presence of amisa e o'f act-e1. 'erators,said accelerators comprising the re action product ofdinitrochlorbeiilz'ene endure potassium salt ofInercapto-beiizo-thiazole, and a secondary amine accelerating coinpound.p I

41. The process of producing vulcanized if -1'-1 I rubber which comprses heating rubber and sulfur in the presence of a mixtu e, ofafcc'elerators, said accelerators comprising the re action product ofdipitrpchlorbenz'ene and the potassium salt of mercapt-o-beazathigazole, and an aryl substituted secondary amine accelerating compound.

42. The process of producing vale-seized rubber which comprises heatingrubber sulfur in the presence of a vulcanization accelerating productcontaining the reaction product of dinitrochlorbenzene and an alkalinesalt-of m'ercapto benzo thiazole as a coin stituei'it thereof. 7 p h H c43 The process of producing vulcanized rubber which comprises. heatingrubber and sulfur in the presence of a vulcanifz'at'ion' ac celerati'ngproduct containing the reaction product of dinitrochlorben 'zeneand thetassium salt of mercapto-benzo-thiazole as a vulcanized rubber productprepared by heating rubber and sulfur in the presence of a mixture ofaccelerators, said accelerators comprising a reaction product ofdinitrochlorbenzen and an alkaline salt of mereapto-benzo-thiazole', anda basic organic nitrogen-containing vulcanization accelera tor.

pared by heating rubber and sulfurin the accelerators comprising thereaction product of dinitrochlorbenzene and t-he potassium salt ofmercapt'o-benzo thiazole, and a basic 45. vulcanizedif l h fro i'i'sorganic nitrogen-containing vulcanization accelerator.

4:6. The vulcanized rubber product prepared by heating rubber and sulfurin the comprising an organic amine and the reaction producto-fdinitrochlorbenzene and the potassium salt of mercapto-benzo-thiazole.

Signed at New York, county and State of presence of a mixture ofaccelerators, said New York, this 23rd day of February, 1928. 3'

accelerators comprising the reaction product of dinitrochlorbenzene andthe potassium salt of mercapto-benzo-thiazole and a secondary amineaccelerating compound.

47. The vulcanized rubber pro-duct prepared by heating rubber and sulfurin the presence of a mixture of accelerators, said acceleratorscomprising the reaction prod uct of dinitrochlorbenzene and thepotassium salt of mercapto-benzo-thiazole, and an. aryl substitutedsecondary amine accelerating compound. 7

48. A vulcanization accelerator mixture comprising an aryl substitutedsecondary amine accelerating compound and QAt-dinitrophenyl benzothiazylsulphide.

49. The vulcanized rubber product prepared by heating rubber and sulfurin the presence of a vulcanization V accelerating product containing thereaction product of dinit-rochlorbenzene and an alkaline salt ofmercapto-benzo-thiazole as a constituent thereof.

50-. The vulcanized rubber product prepared by heating rubber and sulfurin the presence of a vulcanization accelerating prodnot containing thereaction product of dinitrochlorbenzene and the potassium salt ofmercapto-benzo-thiazole as a constituent thereof.

51. A vulcanization accelerator mixture comprising an organic amine anda compound containing the group R(l'|J-SY compound and a compoundcontaining the 7 group Where Y is the methyl carbon atom of asubstituted methyl group that does not contain 0 or S doubly bonded toY, which compound hydrolyzes in aqueous alcohol in the presence ofsodium hydroxide, at least as rapidly as diphenyl-methyl dimethyl'dithiocarbamate under the same conditions.

53. A vulcanization accelerator mixture SIDNEY M. CADWVELL.

